Process for coloring nylon fiber



Patented Dec. 22, 1953 2,663,613 PROCESS FOR COLORING NYLON FIBER Joseph Whitton Gibson,

assignor to E. I. du Pon l any, Wilmington, ware No Drawing. Application Jr., Penns Grove, N. J., t de Nemours and Com- Del., a corporation of Dela- May 10, 1950,

Serial No. 161,267

8 Claims.

In copending application Serial No. 161,265 of even date herewith, I am describing and claiming a general method for improving the process of coloring heat-stable, hydrophobic textile fiber such as nylon, polyacrylonitrile fiber and polyethylene terephthalate fiber. The improvement consists in subjecting the fiber, after impregnation with the selected coloring material and drying, to a heat treatment in the absence of moisture at a temperature between 180 and 250 C. This invention is in the nature of a species under the above general case, and concerns itself primarily with nylon fiber.

Nylon can be dyed with many classes of dyes; however, relatively long dyeing times are required and the dyeings are usually not level. Level dyeings are obtained on nylon filament only with dispersed colors which are suitable for the dyeing of cellulose acetate, but here the dyeings have insufficient lightand wash-fastness for many practical uses.

Accordingly, it is an object of this invention to provide a, process for coloring nylon fiber under novel conditions whereby to produce uniform dyeings and to accelerate fixation to a point where the process becomes adapted for continuous operation. Additional important objects of this invention will appear as the description proceeds.

These objects are achieved according to this invention by subjecting the nylon fiber to a special heat-treatment after impregnating the same, in ordinary manner, with the selected coloring material from an aqueous medium. For instance, the fiber may be padded with an aqueous solution or suspension of the selected coloring material (that is, dye or intermediate for dye), or it may be printed with a thickened, aqueous printing paste containing said coloring material. The impregnated fiber is then dried, and then subjected to a heat treatment at a temperature of between 180 and 230 C., for a brief interval of time. This time interval is usually less than 1 minute, and may in some cases be as brief as seconds. I find, however, that nylon fiber withstands the prescribed range of temperature for considerably longer periods. It is therefore possible to practice my invention with longer heating periods, say up to 2 or even 3 minutes, provided the system of apparatus available is such as to make continuous operation under these conditions economical.

The application of my invention to nylon results first of all in a speedier fixation of the color upon the fiber, thereby adapting the process operation, that is the dyeing of fabric from a continuous roll. Also, with some classes of dyestuffs, espectially acid wool dyestufis, where the ordinary processes produce streaky, uneven dyeings upon nylon, my invention produces uniform dyeings, pleasing in appearance.

In general, the colors which are applicable by my invention are those which will dye nylon from an aqueous dye bath at the boil either neutral or slightly acid (pH 7 to pH 3). These include the following classes of colors:

Acid wool dyes. (These are usually azo dyes possessing SOaH groups and simple anthraquinone compounds having sulfonic acid groups.)

Metallized, water-soluble and water-insoluble azo dyes. (These are usually ortho-hydroxy-azo dyes, aftertreated with compounds of chromium, nickel, copper or other polyvalent metal.)

Cellulose-acetate dyes. (These are generally azo dyes free of SOaH groups, and simple anthraquinone derivatives having amino or bydroxy groups, but no SOaH groups.)

Basic dyes (whether water-soluble or not) Direct cotton dyes (usually azo dyes having SOaH or SOaNa groups).

Sulfur dyes in conjunction with sodium sulfide. (The latter aids in dissolving the sulfur color, forming the so-called sulfide vat.)

Mercaptolated or thiocyanated dyes, that is dyes which while belonging on their own merits to some other standard class are converted into sulfide-vattable dyes by the introduction of SH groups or SCN groups. See for instance, Fox U. S. P. 2,369,666 and Haddock U. S. P. 2,342,662.

Furthermore, I find that in lieu of the finished dyestuff or pigment I often may employ intermediates adapted to yield the desired coloring compound upon heating. For instance, I may impregnate the fiber with a soluble, leuco ester of a vat dye. Then in the heating step the leuco ester becomes converted to the oxidized or keto form. Or again, I may pad the fiber with the components of an azo dye, for instance an azoic coupling component and an aryl amine and subject the impregnated fiber, after drying, to a heat treatment as above described, to effect penetration of the components into the fiber. When the fiber is then treated with an aqueous diazotizing bath, with or without subsequent alkalization (Cf. British Patent No. 629,452), an azo dye is formed within the fiber.

The exposure to heat may be achieved in any available apparatus suitable for supplying dry heat at the temperature interval of to 230 better for continuous C. For operating on a continuous fabric or yarn, a heated drum will naturally be the most convenient form. Other methods, however, may be restorted to, for instance passing the fabric through a molten metallic bath (such as Cerrobend, a low-melting lead alloy), through a flue drier, or under infra-red radiation.

Following the heat treatment, the fabric is preferably subjected to a soaping operation to remove any residual, loosely adhering. superficial pigment particles. The fiber is then rinsed and dried.

Without limiting my invention, the followin examples are given to illustrate the details of operation. Parts mentioned are by weight.

Example 1 A 2% solution of an acid green anthraquinone dye, C. I. 1078, was padded onto filament nylon fabric. The fabric was dried and passed through a due drier, maintained ail-215C at such a rate that the exposure time was all seconds. The so-ebtained dyeing was scoped for five minutes at 11 C. in a solution containing g./l. of sodium oleate. A level. medium green shade was obtained which eithihitedgood' washinglightand crocking-fastness. A similar dyeing prepared by dyeing in a similar color solution at the boil exhibited similar dastnces properties but contamed pronounced wasp streaks.

Other water-soluble colors applied to nylon by the same procedure were:

Color Employed 23 3 all slet C- I- 1020",.- Violet Act, Blue, 0. I. 1088... he. lied BingG. I. 289

The p-tolyl den-iv tlve oi the dyestuflof Example H,

U. VS. 1. 2.124.638. Brown.

Example 2 Thehalf-chromed form or the dyestui! of Wi ie 2.13.8.9. 1.623.005" Orange 4 (o-hydroxy phenylazo) -3-methyl-1 7 phenyhfi-pyrazolone, nickeled Yellow a (2 nitro p tolylaeo) acetoaeetaamde Yellow Vatdye, 0.1 1228 Red Dyestuir made according to'Example-ae,

U. 8. P. 2,212,925,1131118 l-BlIl-iIIO-- aniline-communicate Scarlet Example 3 an aqueous bath was prepar containing 5% hr weieht oi scdiumdichronmte and 5% or the disco drepremred by c upling ammo-enamnh nol and lamino d-"nenhthalenesulfonic acid to m-phenylene diamine. mien fabric. was padded with this sohndenrdried. and passed between twometal sur.=maintamed at 205 C.- in such a way that theesxpesure time was so 4 seconds. The fabric was soaped for 5 minutes at 71 C. with 5 g./l. of sodium oleate. A brown dyeing was obtained which exhibited excellent crock-fastness and fair light-fastness.

Example 4 A 5% aqueous dispersion of 4-(4'--nitrophenylazo) -2,5-xylidine was prepared by warming the dyestuif paste and water at 60 C. with stirring until completely dispersed. The dispersion was then padded onto a nylon fabric. The squeeze rolls were adjusted to give a pick-up of 30%. The fabric was then dried and passed through a flue drier, maintained at 190 C., in such a way that the exposure time was 30 seconds. It was then soaped as described above. A bright orange dyeing was obtained which exhibited good crockingand fair washingand light-fastness.

Other colors applied to nylon by the same procedure and with substantially equal results were:

Color Employed ggg fi l-amino-4-hydroxy-anthraqulnone Red. l.4,5,8-tetramino-anthraquinone Blue.

Example 5 A paste containing the following ingredients was prepared:

two metal surfaces maintained at 225" C. in such a waythat the exposure time was forty seconds. The fabric was soaped for 5 minutes at 71 C. with 5 g./l. of sodium oleate. A green print was obtained that wasbluer but duller than a similar print by standard printing methods.

Other colors printed successfully on nylon by the same procedure were:

Color Employed %3 1-aminoi-(z-sullo-pteluidino) -2-anthraquinone-sulionie acid, disodium salt Blue. The dyestufl of Example 1, U. S. P. 1,724,663 Orange 'lhe half-chromed form of the dyestu-fl of Example 2,

U. S. P. 1,623,005 D0.

Example 6 A mixed dye bath was prepared as follows:

Parts Half-chromed azodye of Example 2,17. S. P.

1,623,005 2.25 Direct Yellow (C. I. 364) 0.15 1 amino 4 (m -methylo1 anilinol- 2 anthraquinone sulienic acidsodium salt.- 2.25 Water 106 The mixture was warmed to 60 C. and stirred until the dyes were completely dissolved. Nylon tow was then padded inthis solution dried and passed through a dryer maintained at 225 C. in such away that theexposu-re timewas 60 seconds. The tewwas seeped fort; minutes at '71 U. with 5 9.1 1. 0! 0166459. All olive dyeing was obtained which exhibited good crocking-, lightand wash-fastness.

A similar dyeing is obtained if using raw stock instead of tow by the above procedure.

Example 7 A 1% solution of anilide of beta-oxy-naphthoic acid in Celloso1vc" (ethylene glycol monoethyl ether) was padded onto nylon fiber and dried. A. 5% solution of m-nitro aniline in 95% ethanol was over-padded on the above padding and dried. The fabric was then passed between two metal surfaces maintained at 205 C. in such a way that the exposure time was seconds. It was then treated for five minutes at 100 C. with a solution of 3 g./l. sodium nitrite and 3.7 g./l. hydrochloride acid. A medium orange shade was obtained which exhibited excellent crockfastness.

The same fibers were also dyed by the same procedure except. for selecting different amines, with the following results:

- bade 0b- Amine Selected tamed Mm- Z-nitro-p-ioluirliuo Red. 4,4-di-o-n.nisldino Violet.

It will be clear from the above examples that my invention is applicable with a wide variety of is possible setting in one continuous operation.

The class of nylon fibers with which this invention deals is well known in the art, and refers to a group of film-forming polymeric amides. See for instance, Carothers, U. S. P. 2,071,250, 2,071,253 and 2,130,948.

I claim as my invention:

1. A process for continuously coloring nylon fiber, which comprises impregnating the same continuously with an organic from an aqueous medium, drying continuously the then continuously than 190 C. and not greater than 230 C., for a period of time of from 20 to 60 seconds, whereby to effect fixation terial, and the heating step being followed by washing to remove superficially disposed surplus coloring material.

4. A process as in claim 3, the aqueous bath comprising a dispersion of a water-insoluble cellulose-acetate dye.

5. A process as in claim 3, the aqueous bath comprising a metallized azo dye.

6. A process as in claim 3, the aqueous bath comprising a solution of an acid dye.

7. A process as in claim 3, the aqueous bath comprising an aqueous solution of a watersoluble basic dye.

8. A process as in claim 3, the aqueous bath comprising an aqueous sulfide-vat of a sulfur color.

JOSEPH WHITTON GIBSON, JR.

References Cited in the file Of this patent UNITED STATES PATENTS OTHER REFERENCES Silk Journal and Rayon World for February 1947, page 55.

Technical Bulletin for June 1949, volume 5, Number 2, pages 82 to 103, published by Du Pont, Wilmington, Delaware.

Rayon Textile Monthly for September 1946, page (496).

Textile Colorist for December 1943, pages 551 to 553. 

1. A PROCESS FOR CONTINUOUSLY COLORING NYLON FIBER, WHICH COMPRISES IMPREGNATING THE SAME CONTINUOUSLY WITH AN ORGANIC COLORING MATTER FROM AN AQUEOUS MEDIUM, DRYING CONTINUOUSLY THE IMPREGNATED FIBER, AND THEN CONTINUOUSLY SUBJECTING THE SAME TO A HEAT TREATMENT IN THE ABSENCE OF MOISTURE AT A TEMPERATURE NOT LESS THAN 190* C. AND NOT GREATER THAN 230* C., FOR A PERIOD OF TIME OF FROM 20 TO 60 SECONDS, WHERBY TO EFFECT FIXATION OF THE COLOR WITHIN THE FIBER. 